The LCD (Liquid Crystal Display) possesses advantages of thin body, power saving and no radiation to be widely used in many application scope, such as LCD TV, mobile phone, personal digital assistant (PDA), digital camera, notebook, laptop, and dominates the flat panel display field.
Most of the liquid crystal displays on the present market are backlight type liquid crystal displays, which comprise a liquid crystal display panel and a backlight module. The working principle of the liquid crystal display panel is that the Liquid Crystal is injected between the Thin Film Transistor Array Substrate (TFT array substrate) and the Color Filter (CF). The light of backlight module is refracted to generate images by applying driving voltages to the two substrates for controlling the rotations of the liquid crystal molecules.
In the active liquid crystal display, each pixel is electrically coupled to a thin film transistor (TFT), and the gate thereof is coupled to a level scan line, and the drain is coupled to a vertical data line, and the source is coupled to the pixel electrode. The enough voltage is applied to the level scan line, and all the TFTs electrically coupled to the scan line are activated. Thus, the signal voltage on the data line can be written into the pixel to control the transmittances of different liquid crystals to achieve the effect of controlling colors. The driving of the level scan line in the present active liquid crystal display is mainly accomplished by the external Integrated Circuit (IC). The external IC can control the charge and discharge stage by stage of the level scan lines of respective stages. The GOA technology, i.e. the Gate Driver on Array technology can utilize the original manufacture processes of the liquid crystal display panel to manufacture the driving circuit of the level scan lines on the substrate around the active area, to replace the external IC for accomplishing the driving of the level scan lines. The GOA technology can reduce the bonding procedure of the external IC and has potential to raise the productivity and lower the production cost. Meanwhile, it can make the liquid crystal display panel more suitable to the narrow frame or non frame design of display products.
In present large scale LCDs, the color washout phenomenon under wide view angle happens and the situation particularly becomes more obvious in the Vertical Alignment (VA) type LCDs. For improving the color washout under wide view angle of the large scale VA type liquid crystal display, the Charge Share pixel design is utilized in prior art to reduce the color washout. The GOA circuit of each stage outputs the charging scan signal and the charge sharing scan signal (Charge & Share gate) via a sequence signal line at the same time, which not only increases the loading of the scan line and the sequence signal line but also degrades the output quality of the scan signal, and meanwhile the stress of the IC is increased. On the other hand, the charging scan signal and the charge sharing scan signal are outputted by the same TFT. The waveforms of the two are consistent, which is not good to the reasonable design of the TFT specification.